An attempt to find out how dental students are affected by mercury vapour during their education.Teaching staff of the department of restorative dentistry of the faculty were exposed to amalgam more than the other departments and the teaching staff of the department of periodontology (who never have to work with amalgam) were compared.The increase of mercury concentration in plasma and whole blood in all groups emphasised that mercury vapour can affect all the people in the school environment.Mercury concentration in plasma is high in the students using amalgam for the first time in clinical skills at the beginning of the academic year.The mercury concentration in whole blood is high for dentists working in the department of restorative dentistry – long-term exposure to mercury vapour is more dangerous because of its collection in target organs.Close attention should be given to mercury hygiene in laboratories and clinics ie ventilation controls, waste mercury disposal.